KR100499177B1 - Submersible in-situ oxygenator - Google Patents

Abstract

The present invention relates to an apparatus and method for mixing gas and liquid while mixing solids and sludge at the bottom of a dip tank and simultaneously suspending them. The present invention includes a gas-liquid aerator suitable for submerging below the surface of wastewater in a dip tank. The gas-liquid mixture, which expands at high speed, is discharged from the bottom of the submerged aerator with sufficient force to mix and suspend sludge and solids that settle to the bottom of the dip tank.

Description

Submersible On-Site Oxygen Supply {SUBMERSIBLE IN-SITU OXYGENATOR}

The present invention generally relates to aeration of liquids and solids, and more particularly to apparatus and methods for dissolving oxygen in liquids while stirring liquids and solids containing various chemicals.

Aerobic wastewater treatment is a very economical method for removing harmful chemical wastes in water systems. When oxygen or air is supplied to organisms in wastewater, toxic or harmful chemicals are consumed by the biologicals as food to produce harmless byproducts. Usually, carbon dioxide and water are the main respiratory products.

The cheapest form of the aeration tank is a pond at the bottom of the soil where the soil has been removed from the surface by 10 to 15 feet (3.0 to 4.6 m) below the surface. However, this type of configuration can cause many potential environmental problems. Hazardous chemical compounds can penetrate through the bottom of the soil bottom pond and contaminate the soil or groundwater. EPA will no longer allow wastewater containing terrestrial prohibited chemicals such as benzene to be treated at these facilities due to the risk of contamination. As such, large and shallow soil bottom ponds are losing their status as a desirable type of aeration tank.

A large surface area aeration pond is also a huge evaporation tank where significant amounts of volatile compounds can evaporate into the atmosphere. As the Air Pollution Prevention Act is passed, these facilities can no longer rely on evaporation to remove volatile compounds as a way to meet regulatory standards. As such, many wastewater treatment facilities are being converted to deep tanks above ground. Above ground tanks with steel floors will not allow toxic chemicals to pass through the tank to contaminate the surrounding area and have a smaller surface to volume ratio for temporary release. In Europe and Asia, dip tanks are much more common.

Supplying oxygen to the dip tank is also achievable with conventional wastewater aerators. Surface aerators can only provide a sufficient amount of oxygen to the upper layer of the entire wastewater tank. Microbubble diffusers require high horsepower to compress the air and overcome the hydraulic head of the aerator.

Bacteria or organisms grow inside wastewater treatment tanks consuming dangerous wastes. Bacteria or organisms are called sludges and form wet solids upon separation from wastewater. In general, the separation means is typically centrifugation or filtration. Since the influent will dilute the tank contents, part of the sludge must be recycled back to the aeration tank to maintain substantially high biological concentrations. In order for the organism to function properly, the sludge must be properly suspended and, if separation occurs, will cause poor biodegradation of the waste. Prior art surface aeration devices do not effectively address the problem of sludge at the bottom of the dip tank. The depth of the dip tank is generally in the range of about 30 to 100 feet (9.1 to 30 m), on average 40 to 50 feet (12 to 15 m).

Surface aerators, as disclosed in US Pat. No. 4,681,711, are effective only for depths of about 10 feet (3.1 m). The use of a downward pump impeller as disclosed in US Re 32,562 to increase the dissolution rate of oxygen from the ceiling space is finite in the dip tank. Since this apparatus is fixed on the reaction vessel, it is not possible to optimize the solid suspension. Conventional apparatus using this technique need to increase the stirring speed in order to increase the speed of the liquid discharged from the draft tube. However, practical limits are encountered, such as how fast the helical impeller can rotate. Commercial bearings used in high capacity 24 inch (61 cm) impeller systems can rotate at speeds of 300 to 400 rpm before vibration, and other mechanical problems damage bearings and gearboxes. The high capacity 36 inch (92 cm) impeller may rotate at a speed of 250 to 300 rpm. Even if mechanical difficulties are eliminated, the system will require a huge amount of power for stirring. In many cases, the power required for sufficient agitation to suspend solids and sludge is three to four times the power required for oxygenation. Most of this power is wasted. This does not mean that this energy is wasted, but that the oxygen dissolving function requires only a small amount of energy.

The reason why very high power is needed for agitation is because oxygen bubbles have upward momentum due to buoyancy. The downward pumping impeller carries oxygen bubbles downward by forming a jet stream. The upward buoyancy is the countercurrent to the downward liquid momentum. The downward movement of the gas-liquid stream, the weaker the momentum of the liquid. The jet stream may also spread outward and reduce its speed. At certain points, the jet stream will be so weak that it can no longer carry oxygen bubbles downwards. In this step, the oxygen bubbles will separate from the liquid jet and move upwards in the reverse direction. The liquid spray is too weak to move anything else or stir the bottom portion of the tank.

Another alternative to very high stirring speeds is to provide a separate mechanical stirring system with a surface aeration device. Mechanical agitation systems are installed on the sides and bottom of the tank for the purpose of providing agitation and suspension of solids. However, driving agitators at the bottom of the tank still requires a significant amount of power, thereby increasing capital costs.

Thus, given the problems and deficiencies of the prior art, it is an object of the present invention to provide an apparatus and method for aeration of wastewater in a dip tank.

Another object of the present invention is to provide an apparatus and method for stirring solids in a dip tank.

It is yet another object of the present invention to provide an apparatus and method for agitating solids with aeration of liquid in a dip tank.

It is yet another object of the present invention to provide an apparatus and method for aeration of liquids and agitation of solids in a dip tank using minimal required energy.

Summary of the Invention

These and other objects and advantages apparent to those skilled in the art are achieved by the present invention with respect to devices and methods for the suspension of solids and for dissolving gases that precipitate in a body of liquid. The apparatus of the present invention includes a collector, a liquid pump, and a ballast chamber suitable for submerging in a liquid station and allowing the apparatus of the present invention to float or sink in a liquid station. The collector is suitable for capturing the injurious gas that rises to the surface of the liquid zone and for inducing the intoxication gas into the ceiling space of the device. Liquid pumps, such as impellers or jet pumps, are inexpensive to guide the feed gas from the feed gas inlet along with the gas and liquid and direct the high velocity gas-fluid mixture downwards in the liquid station. In a preferred embodiment, the ballast chamber is suited to be filled with a ballast such as water to submerge the device of the present invention and to be filled with gas to raise the device in a liquid station.

In a preferred embodiment, the collector capturing the noxious gas comprises the surface of the chamber. The surface of the chamber should be of sufficient size to capture the gas at no cost and have a plane that is sufficiently energized to lead the gas to the ceiling space and to the vortex formed by the impeller.

In a preferred embodiment, the fluid pump includes an impeller connected to a rotatable shaft disposed in the draft member. The bleeding member is suitable for directing gas and liquid from the liquid zone into the bleeding member through an opening proximal to the top of the bleeding member located above the impeller and for discharging through the second opening at the bottom of the member. The impeller is connected to the shaft and is suitable for directing gas and liquid into the draft member in the direction of the impeller and forcing the gas-liquid mixture to exit the draft member at high speed. The impeller may be a high performance impeller, in particular a gas dispersion impeller that is helical in shape and suitable for circulating large quantities of gas and liquid. The feed gas stream is led through the feed gas inlet into the ceiling space above the impeller. The feed gas stream may also be introduced directly into the vortex formed by the impeller as the stream rotates into the liquid zone. In the most preferred embodiment, a turbulent promoter which increases the turbulent mixing rate of the gas-liquid mixture may be connected to the shaft.

As another aspect, the apparatus of the present invention provides an adjustable jet aerator, venturi tube, conduit, ballast chamber suitable for lowering and raising the apparatus, and a collector suitable for capturing gas in the liquid station and directing it to the ceiling space It includes.

In a preferred embodiment, the jet aerator comprises a pump suitable for directing liquid from the liquid zone through the inlet and withdrawing the liquid at high speed through the outlet. As a preferred embodiment, the venturi tube can be connected to the jet aerator and include a tapered mean suitable for receiving liquid at high speed from the aerator. One end of the pipe can be connected to the neck of the venturi tube and the other end induces a mixture of gas, such as fresh oxygen and inert gas from the ceiling space below the venturi tube, and the gas mixture back into the venturi tube. Suitable for feeding

In a preferred embodiment, the conduit may be a flexible hose and supply a second gas to the ceiling space.

In a preferred embodiment, the ballast chamber comprises one or more hollow chambers connected to the device. The chamber is filled with a ballast, such as water, to submerge the device and with a ballast, such as air, is suitable for raising the device in the liquid station. It is also desirable for the collector to have a surface that includes the surface of the ballast chamber and has a surface that is large enough to capture the injurious gas rising in the liquid region and a surface inclined to direct and capture the incompetent gas into the ceiling space. .

As another aspect of the present invention, the present invention provides a method of aeration of a liquid zone and suspending solids precipitated in the liquid zone. This method comprises the steps of providing a submersible aerator, submerging the aerator below the surface of the liquid zone, introducing a gas stream into the liquid station, and mixing the gas stream with the liquid zone using the aerator. It includes. In a preferred embodiment, the aeration device injects a high velocity gas-liquid jet into the liquid zone, and the device has sufficient force to suspend solids that settle in the liquid zone.

In a preferred embodiment, the depth of the submerged aerator is adjusted to optimize the suspension of solids that settle in the liquid station. In another preferred embodiment, the depth of the device is adjusted by submerging the chamber by filling the ballast chamber with a ballast until the device reaches the desired depth.

In another preferred embodiment, the injurious gas rising to the surface of the liquid zone is captured by the collector and recycled to the gas-liquid spray.

Features of the invention believed to be novel and characteristic components of the invention are set forth in the claims. The invention is described with reference to the drawings but is not intended to limit the invention. However, the configuration and operation method of the present invention can be more clearly understood through the detailed description according to the accompanying drawings.

Detailed description of the preferred embodiment

Reference is made to Figures 1 to 3 in describing preferred embodiments of the present invention, wherein like reference numerals designate like features of the present invention. Features of the invention are not necessarily drawn to scale in the drawings.

As shown in FIGS. 1 and 2, the apparatus of the present invention includes a gas-liquid aerator 50 suitable for submerging in a dip tank 30 containing liquid 32 and solids 33. In a preferred embodiment, the liquid 32 is wastewater and the solids 33 are sludge formed in the dip tank 30. The aeration device 50 includes a liquid pump, such as an impeller, a jet flow pump or a positive displacement device, which can induce liquid and gas and move the liquid and gas downward at high speed. In a preferred embodiment, the aerator 50 comprises a submersible motor 16 and a rotatable shaft 20 connected to a motor support plate 18. The impeller 22 is connected to the shaft 20, and the impeller 22 and the shaft 20 are preferably arranged inside the draft tube 24.

In the draft tube 24, one or more openings 28 and gas-liquid mixture 36 for passing gas such as liquid 32 and oxygen into the draft tube 24 pass through the impeller 22. At least one second opening 68 is formed to allow discharge from the draft tube 24. The opening 28 is preferably located at a point above the impeller 22, while the opening 68 is located at a point below the impeller 22, preferably at the bottom of the draft tube 24.

The aeration device 50 comprises one or more ballast chambers 10 suitable for filling the device with a ballast for the purpose of submerging the device below the surface liquid 32. The ballast chamber 10 is preferably a hollow stainless steel float and is wholly sealed except for the fluid valve 12 and the air valve 14 which allow the ballast to flow in and out of the ballast chamber 10. The fluid valve 12 allows fluid ballast, preferably water, to pass in and out of the chamber. The air valve 14 allows gas ballast, preferably air, to pass in and out of the chamber 10. The chamber is submerged by introducing fluid into the chamber 10, while the chamber rises in the liquid 32 by introducing air into the chamber 10.

In a preferred embodiment, the bottom surface 80 of the chamber 10 is conical shaped or inclined at an angle such that the outer edge 82 of the chamber 10 is wider than the inner edge 84 of the chamber 10. . The chamber 10 is of sufficient size and shape to allow the gas 38 to rise up in the liquid 32 to be captured by the bottom surface 80 of the chamber 10, and the shape or The angle is inexpensive, leading gas 38 into the ceiling space 48 and the opening 28. The shape of the chamber 10 is preferably suitable for capturing insoluble gas particles 38 that rise up in the liquid 32, but other devices or means for capturing the insoluble gas particles and leading them to the ceiling space 48. Can also be used. These devices may include baffles, wings, partitions, or electromechanical devices that trap the rising costly gas 38 and direct it to the ceiling space 48.

Motor 16 is preferably an electric or air motor. In a preferred embodiment, the motor 16 drives a gear box 46 that is connected to the shaft 20. The shaft 20 passes through the seal 44 and the motor support plate 18 and passes through the draft tube 24.

The seal 44 is used to position the shaft 20 on the motor support plate 18 and to protect the shaft 20 from the support plate while allowing the shaft 20 to rotate freely. The impeller 22 is fixedly connected to the shaft 20 in the draft tube 24 and is preferably a high capacity or gas dispersion impeller pumping downward. In a preferred embodiment, the impeller 22 has a helical shape to circulate a large volume of gas and liquid. Optionally, a turbulent promoter or turbine 42 can be added to the shaft 20 to increase the turbulent mixing rate of the gas and liquid.

In a preferred embodiment, the conduit 26 passes through the motor support plate 18 and enters the ceiling space 48. This region between the edges 84 is referred to as the ceiling space 48 in which gas accumulates. Conduit 26 may extend below the bottom of the edge of motor support plate 18 and is used to introduce gas, preferably oxygen, into ceiling space 48. In a preferred embodiment, oxygen is supplied to conduit 26 and passes through motor support plate 18. Oxygen is supplied to the ceiling space 48 above the draft tube 24, with the result that the vortices induced by rotating the impeller 22 pass the gas-liquid mixture down the draft tube 24 through the opening 28. Can be induced. Conduit 26 may also extend below the surface of liquid 32 so that oxygen can be supplied directly to the vortex formed by rotating impeller 22.

In operation, the aerator 50 is submerged below the surface of the liquid 32. Any conventional means may be used to submerge the aeration apparatus 50. In a preferred embodiment, the aerator 50 is submersible by filling the ballast chamber 10 with the ballast 34. The ballast chamber 10 may comprise a hollow chamber or a flotation device that may be filled with the ballast 34. The ballast chamber 10 is of sufficient size to allow the aerator 50 to submerge into the liquid 32 below the surface when it is filled with the ballast 34, even in part. The ballast 34 is preferably a filling liquid such as water and is preferably introduced into the ballast chamber 10 via the fluid valve 12. Air discharged from the ballast chamber 10 by the ballast 34 may be discharged through the air outlet 14. When the aerator 50 is submerged, a supply hose may be connected to both the fluid valve 12 and the air valve 14 to perform a filling and vacuum process. Each valve 12 and 14 may be adjusted and monitored to maintain the same amount of fluid uptake and air release within the chamber 10, particularly where more than one chamber 10 is used. When using the ballast 34 to fill the chamber 10, the aerator 50 will submerge below the surface of the wastewater 32 in the dip tank 30. In order to raise the aeration device 50, air is filled into the chamber 10 through the air valve 14. This air filling causes the ballast to be discharged out of the chamber 10 through a valve 12, preferably a dip tube. Using this method, the depth of the device 50 inside the tank 30 is easily adjusted. The position of the chamber 10 should be lowered and raised in a horizontal and constant manner.

Since the rotating helical impeller will generate an upward thrust force, it is necessary to run the motor 16 before the final depth adjustment. In addition, gas flow to conduit 26 needs to be started. In addition, the increase of oxygen into the ceiling space 48 will increase the buoyancy of the device. After the aeration device 50 has been operated in a steady state, final adjustments are made by adding additional ballast 34, preferably air or water, into the chamber 10. Guide cables or guide rods 90 may be attached to the aerator 50 so that the submerged device is in the center of the desired location in the tank 30.

The rotating impeller 22 will guide oxygen and wastewater 32 through the opening 28 into the draft tube 24. The gas-liquid mixture 36 will exit the draft tube 24 as a high velocity jet and preferably expands at an angle of about 20 °. Based on momentum conservation, the velocity of jets 36 will decrease with its expansion. The depth of the aerator 50 in the dip tank 30 is adjusted so that the gas-liquid jets 36 have a sufficient speed to mix and suspend the sludge 33 with the solids that settle at the bottom of the tank 30. do. Samples may be taken at various depths of tank 30 to properly suspend solids and sludge. The rotational speed of the impeller 22 as a whole is independent of the requirements of the solid suspension.

By submerging the aeration device 50 in the wastewater 32 contained in the dip tank 30, an unexpected advantage is achieved over the surface floating aeration device due to the additional hydraulic head for mass transfer. Since oxygen solubility increases under pressure, the rate of oxygen transfer will increase as the aerator 50 submerges deeper into the tank 30.

Oxygen utilization is also increased by submerging the aerator 50 into the wastewater 32. In general, the non-hazardous gas from jets 36, ie oxygen bubbles 38, will rise and, as a preferred embodiment of the present invention, will be recaptured and led to draft tube 24. Vortex generated by the impeller 22 causes these oxygen bubbles 38 to be directed through the opening 28 and recycled through the impeller 22. However, a fraction of the oxygen bubbles 40 will escape around the chamber 10 without being trapped and recirculated. Although a small amount of oxygen bubbles 40 may escape around the submerged chamber, the escaped oxygen bubbles 40 still have a significant travel distance upwards before reaching the surface of the liquid 32. Thus, only less than half of the escaped oxygen bubbles 40 can actually reach the liquid surface. This improves oxygen utilization. Moreover, the leaving oxygen bubble 40 will also provide some agitation and oxygenation on top of the dip tank.

In the case of the present invention, the power input and rotational speed of the aerator 50 can be optimized based on the oxygen demand. This is not related to solid suspension requirements. Thus, in the case of the present invention, both capital and power costs are greatly reduced.

As another aspect of the invention, the adjustable jet aerator 70 is submersible hollow float 10 or ballast chamber, with the jet stream 56 with oxygen tapering downwards as shown in FIG. 3. It can be installed on. The adjustable jet aerator provides, unlike fixed jet aerators, the flexibility of variable mixing strength at the bottom of the tank according to variable solids loading and process conditions.

Although ballast chamber 10 is shown as a single chamber in this embodiment, chamber 10 may also include one or more hollow chambers. In a preferred embodiment, a chamber 10 shaped as shown in FIG. 3 is used to trap innocent gas particles that rise up in the liquid 32 and direct them into the ceiling space 48. As mentioned above, any means can be used to capture these particles and these means do not depend on the shape of the chamber 10.

As shown in FIG. 3, the liquid momentum is provided by a pump 66 driven by a motor 52. The jet aerator pump 66 may be mounted on top of the float 10 or outside of the liquid 32. Liquid 32 is introduced into pump 66 through inlet 54 from wastewater treatment plant or dip tank 30. The liquid exits the pump 66 at high pressure (eg, 15-200 psig) through the pump outlet 56 and passes through the venturi tube 58. The narrow middle of the venturi tube 58 is converted into potential energy and kinetic energy so that the pressure decreases as the speed increases to the maximum. Indeed, the pressure may drop negatively and a vacuum may be generated in the neck of the venturi tube 58. Pipe 60 may be used to connect the ceiling space 48 under the chamber 10 to the neck 64 of the venturi tube 58, with the resulting vacuum being a gas from the ceiling space 48. May be introduced into the venturi tube 58 to form a two-phase flow.

Oxygen is supplied to the inlet 26 at the top of the chamber 10 via a flexible oxygen hose 72. Oxygen may be injected directly into the ceiling space 48 or may be injected directly into the liquid 32 using, for example, a sparger. Fresh oxygen supplied into the ceiling space 48 through the flexible oxygen hose 72 is generated from any inexpensive oxygen bubbles 38 that rise up in the liquid 32 that are captured and reintroduced into the ceiling space 48. Will be mixed with recycled oxygen. The pressure in the ceiling space 48 located below the chamber 10 will depend on the depth of the unit below the surface of the liquid 32. While the amount of oxygen (fresh and recycled oxygen) entering the venturi tube 58 will vary, the speed of the pump 66 can be adjusted to meet different oxygen dissolution requirements.

At very deep depths (eg more than 100 ft.), Recycled oxygen is no longer needed and fresh oxygen can be supplied directly to the venturi tube 58. Alternatively, the venturi tube 58 is not necessary because fresh oxygen is supplied directly into the pump discharge pipe 56 under pressure to form a gas liquid jet stream 36.

As such, the present invention provides an apparatus and method for agitating simultaneously while aeration of wastewater and solids in a dip tank using minimal required energy.

As described above, the present invention has been described in detail with certain preferred embodiments, but it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art through the foregoing description. Accordingly, the following claims are to be regarded as including such alternatives, modifications and variations without departing from the scope and spirit of the invention.

As described above, the present invention provides an apparatus and method for aeration of wastewater in a dip tank with minimal energy, an apparatus and method for agitating solids in a dip tank, and an apparatus and method for agitating solids with aeration of liquid in a dip tank. to provide.

1 is a side view showing the apparatus of the present invention.

Figure 2 is a side view showing the device of the present invention submerged in a deep tank.

3 is a side view showing the jet aeration apparatus of the present invention.

* Description of the symbols for the main parts of the drawings

10 ballast chamber 12 fluid valve

14: air valve 22: impeller

24: draft tube 30: dip tank

32 liquid 33 solid

48: ceiling space 50: aeration device

Claims (10)

Apparatus for the suspension of solids and gas dissolved in the liquid station, suitable for submerging in the liquid station, a) a collector suitable for capturing non-hazardous gas rising to the surface of the liquid zone and directing the captured non-hazardous gas into the ceiling space of the device; b) the feed gases derived from the feed gas inlet from the feed gas inlet with the undesired gas and liquid induced by the collector into the ceiling space to mix and suspend the suspended solids and sludge at the bottom of the liquid zone and dissolve the undesired gases; Together a fluid pump for discharging downward at high speed towards the bottom of the liquid station as a gas liquid mixture; And c) one or more ballast chambers connected to the device, suitable for submerging the device into the liquid station by filling with a first ballast, and suitable for raising the device up in the liquid station by filling with a second ballast. Apparatus for dissolving gas and suspension of solids precipitated in the liquid station comprising a. 2. The apparatus of claim 1 wherein the fluid pump comprises an impeller connected to a rotatable shaft disposed within the draft member. 2. The apparatus of claim 1, wherein the collector has a ballast chamber surface sized to capture the insoluble gas, the ballast chamber surface having a planar surface that is inclined to guide the insoluble gas into the ceiling space. Apparatus for dissolving gas and suspension of solids precipitated in a liquid station. Apparatus for the suspension of solids and gas dissolved in the liquid station, suitable for submersion in the liquid station, a) an adjustable jet aerator suitable for directing liquid from said liquid zone and discharging said liquid at high speed; b) a venturi tube connected to said jet aerator, having a narrow middle, adapted to receive liquid from said aerator at high speed; c) a first end is connected to the neck of the venturi tube, and a second end is suitable for directing the first gas from the ceiling space below the venturi tube and feeding the first gas back to the venturi tube pipe; d) a conduit for supplying a second gas to said ceiling space; e) a ballast chamber attached to the device and adapted to fill with a first ballast to allow the device to submerge in the liquid station and to fill with a second ballast to cause the device to rise in the liquid station; And f) A device for dissolving gas and suspending solids in a liquid station, comprising a collector for capturing the non-hazardous gas rising from the liquid zone and directing the non-hazardous gas into the ceiling space. 5. The apparatus of claim 4, wherein the collector has a ballast chamber surface of a size capable of capturing the innoxious gas, and the ballast chamber surface having a sloped surface to guide the innoxious gas into the ceiling space. , Apparatus for dissolving gas and suspending solids that settle in a liquid station. 5. The suspension according to claim 4 wherein the jet aerator includes a pump having an inlet for inducing the liquid from the liquid zone and an outlet for discharging the liquid at high speed. Device for. A method of aeration of a liquid zone and suspending solids precipitated in the liquid zone, a) providing a submersible aerator; b) submerging the aerator below the surface of the liquid zone; c) introducing a gas stream into the liquid zone; And d) mixing the suspended solids and sludge at the bottom of the liquid zone with the undissolved gases and liquids in the gas stream and the liquid zone using the aeration device to dissolve and dissolve undissolved gases; Exhausting the mixed gas-liquid mixture at a high velocity downwardly toward the bottom of the liquid station, the method of suspending solids and suspending solids in the liquid station. 8. The method of claim 7, further comprising the step of adjusting the submerged depth of the aeration device to optimize the suspension of solids precipitated in the liquid zone, thereby aspirating the liquid zone and suspending solids that settle in the liquid zone. Way. The method of claim 8, wherein adjusting the depth of the aeration device, a) filling a ballast chamber connected to said submersible aerator with a first ballast such that said submersible aerator is submerged below the surface of said liquid zone; b) filling a ballast chamber with a first ballast until said submersible aerator reaches a desired depth in said liquid station; c) venting the first ballast by filling the ballast chamber with a second ballast to cause the submersible aerator to rise to the surface of the liquid zone, which aerated and precipitates in the liquid zone. Method of Suspending Solids. 8. The method of claim 7, further comprising the steps of: a) capturing the non-hazardous gas rising to the surface of the liquid zone; And b) recirculating the insoluble gas into a gas-liquid jet stream. A method of aeration of a liquid zone and suspending solids which precipitates in the liquid zone.